1. Field of the Invention
The present invention relates to a ratchet one-way clutch used in an automatic transmission, a building machine, an agricultural machine and the like, and a stator using such a ratchet one-way clutch.
2. Related Background Art
FIG. 16 is a front view of a stator 101 having a conventional ratchet one-way clutch.
Now, a construction of such a stator 101 will be explained. The stator 101 comprises a vane wheel 107 and a one-way clutch 115 disposed inside the vane wheel 107.
The ratchet one-way clutch 115 incorporated into the stator 101 includes an inner race 102, an outer race 103 disposed for relative rotation with respect to the inner race 102 and concentric with the latter, pawl members 104 housed in pockets 112 of the outer race 103 and adapted to transmit torque, and biasing springs 105 for biasing the respective pawl members 104 radially inwardly, and the inner race 102 is provided at its outer periphery with recessed portions 106 into which the pawl members 104 can fit.
Further, the outer race 103 is provided at its inner periphery with stress relieving recessed portion 130 for dispersing stress generated when the pawl members 104 fit into the recessed portions 106.
The outer race 103 directly abuts against an outer peripheral surface and side surfaces of the inner race 102, so that relative rotation between the outer race 103 and the inner race 102 is permitted. The inner race 102 and the outer race 103 include portions having a sliding bearing function.
First recessed portions 119 for containing damper springs 108 are formed in an outer peripheral surface of the outer race 103 equidistantly along a circumferential direction, and recessed portions 129 corresponding to the first recessed portions are formed in an inner peripheral surface of the vane wheel 107 equidistantly along the circumferential direction. Each of the damper springs 108 extends in the circumferential direction and has one end abutting against a side wall of the first recessed portion 119 provided in the outer race 103 substantially perpendicular to the circumferential direction and the other end abutting against a side wall of the recessed portion 129 provided in the vane wheel 107 substantially perpendicular to the circumferential direction.
Further, second recessed portions 110 are formed in the outer peripheral surface of the outer race 103. Projections 109 which can protrude into the second recessed portions 110 are provided on an inner peripheral surface of the vane wheel 107 at positions corresponding to the second recessed portions 110. When the vane wheel 107 is rotated relatively with respect to the outer race 103, the damper springs 108 are flexed, and, before contraction permitting amounts of the damper springs 108 are reached, the projections 109 of the vane wheel 107 abut against the second recessed portions 110. Thus, flexed amounts of the damper springs 108 are limited, thereby preventing yielding and damage of the damper springs 108. Namely, a damper mechanism 116 is constituted by the first and second recessed portions of the outer race 103 and the recessed portions 129 and the projections 109 of the vane wheel.
With the above-mentioned arrangement, shock generated when the pawl members 104 of the one-way clutch 115 are fitted into the recessed portions 106 of the inner race 102 is transmitted from the outer race 103 to the damper springs 108 and is absorbed by the damper springs 108. Even if the shock generated when the pawl members 104 are fitted into the recessed portions 106 is so great that it cannot be absorbed by the springs, the second recessed portions 110 of the outer race 103 lock the projections 109 of an inner ring 117, thereby limiting the flexed amounts of the damper springs 108. Thus, the yielding and damage of the damper springs 108 can be prevented.
In the stator having the above-mentioned ratchet one-way clutch 115, when a direction of the relative rotation between the inner race 102 and the outer race 103 is a direction for achieving engagement of the pawl members 104, the torque is transmitted; whereas, then the direction is a direction for not achieving engagement of the pawl members 104, idle rotation is generated, with the result that the torque is not transmitted.
In the above-mentioned conventional stator, because of wear due to a sliding movement between the pawl member and the outer race and wear of bearing mechanisms constructed between the inner race and the outer race and between the inner race and the vane wheel, there was a tendency that metallic powder generated by the wear of various parts and foreign maters such as dirt are accumulated within the one-way clutch for example, within the stress relieving recessed for relieving the stress generated by the engagement of the pawl members.
If the foreign matters exist within the one-way clutch or the stator, not only an operation of the one-way clutch or the stator may be obstructed, but also various parts constituting the one-way clutch or the stator may be damaged.
An object of the present invention is to a stator in which metallic powder generated by wear of bearing mechanisms between pawl members and an outer race and between an inner race and the outer race and between the inner race and a vane wheel and foreign matters such as dirt within a ratchet one-way clutch of the stator are discharged outside, thereby preventing a poor operation.
Another object of the present invention is to provide a stator in which a good assembling ability for damper springs can be achieved.
To achieve the above objects, according to one aspect of a one-way clutch of the present invention, there is provided a ratchet one-way clutch comprising an inner race, an outer race disposed for a relative rotation respect to the inner race and in concentric with the latter, a recessed portion formed in one of an outer periphery of the inner race and an inner periphery of the outer race along a circumferential direction, a pawl member formed on the other of the outer periphery of the inner race and the inner periphery of the outer race and adapted to be fitted into the recessed portion, a spring for biasing the pawl member toward the recessed portion, and a pocket for containing the pawl member and the spring, and wherein a discharge path is formed in the outer race.
Since the discharge path is formed in the outer race, metallic powder generated by wear between various member constituting the one-way clutch can be discharged.
According to another aspect of the one-way clutch of the present invention, the discharge path is a groove extending in a radial direction of the outer race.
According to a further aspect of the one-way clutch of the present invention, the discharge path is communicated with a recess for relieving stress provided in an inner periphery of the outer race.
According to a still further aspect of the one-way clutch of the present invention, the discharge path is a hole passing through the outer race in an axial direction.
According to a further aspect of the one-way clutch of the present invention, there are provided an inner race, an outer race disposed for a relative rotation respect to the inner race and in concentric with the latter, a recessed portion formed in one of an outer periphery of the inner race and an inner periphery of the outer race along a circumferential direction, a pawl member formed on the other of the outer periphery of the inner race and the inner periphery of the outer race and adapted to be fitted into the recessed portion, a spring for biasing the pawl member toward the recessed portion, a pocket for containing the pawl member and the spring, and a pocket formed in an outer periphery of the outer race and adapted to contain a damper spring, and the pocket for containing the damper spring is provided with an assembling window passing through the outer race in an axial direction.
According to a still further aspect of the one-way clutch of the present invention, the discharge path is further communicated with the pocket for containing the damper spring or a groove formed in the outer peripheral surface of the outer race.
According to the other aspect of the one-way clutch of the present invention, the outer race is made of aluminium.
Further, the stator of the present invention uses the ratchet one-way clutch according to any one of the above-mentioned aspects.
In addition, the stator of the present invention includes a vane wheel having a discharge path.
The discharge path formed in the vane wheel of the present invention is a hole passing through the vane wheel in an axial direction.